Abstract

A paleomagnetic study was carried out on 70 cores from 11 sites on the Helikian (1346 ± 30 m.y.) Mistastin pluton, which lies in the Churchill Province about 120 km north of the Grenville Front. Primary magnetization could not be recovered from four of the sites, which were very weakly magnetized. The magnetization of three of these was dominated by a steeply-dipping down direction, which is thought to reflect the recent earth's field direction and may have originated during the process of recent weathering. The primary magnetization was isolated from the remaining seven sites, with a mean direction of D = 93.5°, I = 7.0° and α95 = 8.8°. One site was reversely magnetized relative to the rest. The Pacific pole lies at 158.5 °Wand 1.0°S, with A95 = 7.6°. This pole position supports the concept of a clockwise rotation (30° ± 5°) of the northeastern Grenville Orogen during the Helikian.

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